Adjacent Normal Brain Research Articles

TMET-31. OXIDATIVE STRESS INDUCED PROTEIN AGGREGATION VIA GGCT PRODUCED PYROGLUTAMIC ACID IN DRUG RESISTANT GLIOBLASTOMA

Abstract Drug resistance is a major barrier to cancer therapies and remains poorly understood. Recently, non-mutational mechanisms of drug resistance have been proposed where a more plastic metabolic response can play a major role. Here, we show that upon drug resistance, glioblastoma (GBM) cells have increased oxidative stress, mitochondria function, and protein aggregation. Gamma (y)-glutamylcyclotranserase (GGCT), an enzyme in the y-glutamyl cycle for glutathione production, located on chromosome 7 which is commonly amplified in GBM is also increased upon resistance. We further observe that the byproduct of GGCT – pyroglutamic acid – can bind aggregating proteins and that genetic and pharmacological inhibition of GGCT prevents protein aggregation. Finally, we found increased protein aggregation, GGCT expression, and pyroglutamic acid staining in recurrent GBM patient samples, as well as adjacent normal brain. These findings suggest a new pathway for protein aggregation within drug resistant brain cancer that should be further studied in other brain disorders.

Single-cell dissection of the human blood-brain barrier and glioma blood-tumor barrier

The blood-brain barrier (BBB) serves as a crucial vascular specialization, shielding and nourishing brain neurons and glia while impeding drug delivery. Here, we conducted single-cell mRNA sequencing of human cerebrovascular cells from 13 surgically resected glioma samples and adjacent normal brain tissue. The transcriptomes of 103,230 cells were mapped, including 57,324 endothelial cells (ECs) and 27,703 mural cells (MCs). Both EC and MC transcriptomes originating from lower-grade glioma were indistinguishable from those of normal brain tissue, whereas transcriptomes from glioblastoma (GBM) displayed a range of abnormalities. Among these, we identified LOXL2-dependent collagen modification as a common GBM-dependent trait and demonstrated that inhibiting LOXL2 enhanced chemotherapy efficacy in both murine and human patient-derived xenograft (PDX) GBM models. Our comprehensive single-cell RNA sequencing-based molecular atlas of the human BBB, coupled with insights into its perturbations in GBM, holds promise for guiding future investigations into brain health, pathology, and therapeutic strategies.

IMG-19. CLINICAL UTILITY OF NON-FDG PET-MRI IN CHILDREN WITH CNS NEOPLASMS: A TERRITORY-WIDE STUDY FROM HONG KONG

Abstract INTRODUCTION Magnetic resonance imaging (MRI) is the gold-standard for neuroimaging, yet details from anatomical scans might be inconclusive in certain scenarios. This study aimed to investigate the utility of amino-acid tracer positron emission tomography-magnetic resonance imaging (PET-MRI) based on a territory-wide Pediatric Neuro-Oncology cohort from Hong Kong. METHODS We reviewed the PET-MRI scans of pediatric patients with suspected/confirmed CNS neoplasms co-managed by Hong Kong Children’s Hospital and St. Teresa’s Hospital, Hong Kong from 5/2022-1/2024. Tracers used included C11-MET (n=10, before 5/2023) and F18-FET (n=15, in/after 5/2023). Lesion-to-normal SUVmax ratios (LNRmax) were measured with reference to adjacent or contralateral normal brain structures. RESULTS Twenty-five patients were included (M:F=13:12) with a median age of 10 years (range: 1-17). Anatomical sites of interest were the pituitary (n=13), basal ganglia (n=3), cerebellum (n=3), brainstem (n=2), frontal lobe (n=2), cerebellopontine angle (n=1), and spine (n=1). PET-MRI was performed as part of initial diagnostics in 21, to assess post-operative residual in 2, and for possible relapse in 2. Among those evaluated upfront (n=21), median SUVmax and LNRmax were 1.53 (range: 0.87-2.6) and 0.87 (range: 0.45-1.92) respectively in patients with presumed/confirmed low-grade glioneuronal (n=5) or non-oncologic lesions (n=8), versus 4.75 (range: 2.58-9.6) and 3.26 (range: 1.78-4.9) in patients with histologically/biochemically confirmed high-grade lesions (germinoma=6, high-grade glioma=2). Availability of functional PET imaging was deemed useful for scan interpretation in all 25 patients. Specifically, the use of PET-MRI facilitated decision for radiographic surveillance without biopsy/resection in 12 patients, refined tumor grading in 2 patients with discrepant clinical-histologic features, and allowed response-adapted therapy after serial scans in 5 patients. CONCLUSIONS Our study demonstrates the potential benefits of PET-MRI in the management of children with CNS pathologies. PET-MRI contributes to the diagnosis, monitoring, and treatment guidance of these patients, providing crucial information for clinical decision-making.

TMET-20. TARGETING LINKS BETWEEN METHIONINE METABOLISM AND DNA REPAIR TO IMPROVE GBM THERAPY

Abstract Glioblastoma (GBM) is uniformly lethal due to intrinsic resistance to standard of care radiation (RT) and chemotherapy. Recent studies have identified altered cellular metabolism as a key mediator of GBM RT resistance. Methionine uptake is drastically elevated in GBMs compared to normal cells but whether this impacts treatment resistance is uncertain, as is the metabolic fates of methionine once it enters GBM cells. Here, we find that RT acutely increases the levels of methionine-related metabolites in a variety of RT-resistant GBM models. Stable isotope tracing studies further revealed that RT acutely activates methionine to S-adenosyl methionine (SAM) conversion through an active signaling event through DNA damage response. We developed in vivo 13C5 methionine stable isotope tracing techniques to confirm these findings in orthotopic models of GBM. Pharmacological and dietary strategies to block methionine to SAM conversion slowed the DNA damage repair and increased cell death following RT. These effects are selective to GBMs lacking the methionine salvage enzyme methylthioadenosine phosphorylase (MTAP). Pharmacologic and dietary strategies to inhibit SAM synthesis hindered tumor growth in flank and orthotopic in vivo GBM models when combined with RT. In short, these results highlight a new signaling link between DNA damage and SAM synthesis and define the metabolic fates of methionine in GBM in vivo. Inhibiting the RT-induced SAM synthesis slows the DNA damage repair and augments RT efficacy in GBM. This therapeutic strategy provides scope for combining MAT2A inhibitors with RT in GBMs with impaired methionine salvage and spares the adjacent normal brain.

Enhancing the Reliability of Intraoperative Ultrasound in Pediatric Space-Occupying Brain Lesions

Intraoperative ultrasound (IOUS) may aid the resection of space-occupying brain lesions, though technical limits may hinder its reliability. IOUS (MyLabTwice®, Esaote, Italy) with a microconvex probe was utilized in 45 consecutive cases of children with supratentorial space-occupying lesions aiming to localize the lesion (pre-IOUS) and evaluate the extent of resection (EOR, post-IOUS). Technical limits were carefully assessed, and strategies to enhance the reliability of real-time imaging were accordingly proposed. Pre-IOUS allowed us to localize the lesion accurately in all of the cases (16 low-grade gliomas, 12 high-grade gliomas, eight gangliogliomas, seven dysembryoplastic neuroepithelial tumors, five cavernomas, and five other lesions, namely two focal cortical dysplasias, one meningioma, one subependymal giant cell astrocytoma, and one histiocytosis). In 10 deeply located lesions, IOUS with hyperechoic marker, eventually coupled with neuronavigation, was useful to plan the surgical route. In seven cases, the administration of contrast ensured a better definition of the vascular pattern of the tumor. Post-IOUS allowed the evaluation of EOR reliably in small lesions (<2 cm). In large lesions (>2 cm) assessing EOR is hindered by the collapsed surgical cavity, especially when the ventricular system is opened, and by artifacts that may simulate or hide residual tumors. The main strategies to overcome the former limit are inflation of the surgical cavity through pressure irrigation while insonating, and closure of the ventricular opening with Gelfoam before insonating. The strategies to overcome the latter are avoiding the use of hemostatic agents before IOUS and insonating through normal adjacent brain instead of corticotomy. These technical nuances enhanced the reliability of post-IOUS, with a total concordance to postoperative MRI. Indeed, the surgical plan was changed in about 30% of cases, as IOUS showed a residual tumor that was left behind. IOUS ensures reliable real-time imaging in the surgery of space-occupying brain lesions. Limits may be overcome with technical nuances and proper training.

Pan-cancer analysis: predictive role of TAP1 in cancer prognosis and response to immunotherapy

BackgroundTransporter associated with antigen processing 1 (TAP1) is a molecule involved in processing and presentation of major histocompatibility complex class I restricted antigens, including tumor-associated antigens. TAP1 participates in tumor immunity, and is aberrantly expressed in multiple cancer types;MethodsTranscriptome profiles were obtained from The Cancer Genome Atlas and Genotype-Tissue Expression databases. Genetic alterations, protein distribution, and interaction information for TAP1 were downloaded from cBioPortal, Human Protein Atlas and Compartmentalized Protein–Protein Interaction, respectively. Single-cell analyses of TAP1 across cancers were conducted via the Tumor Immune Single-cell Hub website. Gene set enrichment analysis was employed to investigate TAP1-associated functional mechanisms and processes. Immune cell infiltration was explored using Tumor Immune Estimation Resource 2.0. Pan-cancer correlations between TAP1 expression and immunotherapy biomarkers were explored using the Spearman’s correlation test. Associations with immunotherapy responses were also investigated using clinicopathological and prognostic information from cohorts of patients with cancer receiving immune checkpoint inhibitors.ResultsTAP1 expression was elevated in most cancer types and exhibited distinct prognostic value. Immune cells expressed more TAP1 than malignant cells within most tumors. TAP1 expression was significantly correlated with immune-related pathways, T-lymphocyte infiltration, and immunotherapeutic biomarkers. Clinical cohort validation revealed a significant correlation with immune therapeutic effects and verified the prognostic role of TAP1 in immunotherapy. Western blot assay indicated that TAP1 is upregulated in glioblastoma compared with adjacent normal brain tissues.ConclusionTAP1 is a robust tumor prognostic biomarker and a novel predictor of clinical prognosis and immunotherapeutic responses in various cancer types.

Modulating Nanozyme-Based Nanomachines via Microenvironmental Feedback for Differential Photothermal Therapy of Orthotopic Gliomas.

Gliomas are common and refractory primary tumors closely associated with the fine structures of the brain. Photothermal therapy (PTT) has recently shown promise as an effective treatment for gliomas. However, nonspecific accumulation of photothermal agents may affect adjacent normal brain structures, and the inflammatory response induced during PTT may result in an increased risk of brain tumor recurrence or metastasis. Here, the design and fabrication of an intelligent nanomachine is reported based on Gd2 O3 @Ir/TMB-RVG29 (G@IT-R) hybrid nanomaterials. These nanomaterials enable tumor-specific PTT and eliminate inflammation to protect normal brain tissue. The mechanism involves the rabies virus glycopeptide-29 peptide (RVG29) passing through the blood-brain barrier (BBB) and targeting gliomas. In the tumor microenvironment, Ir nanozymes can act as logic control systems to trigger chromogenic reaction amplification of 3,3',5,5'-tetramethylbenzidine (TMB) for tumor-specific PTT, whereas in normal brain tissues, they scavenge reactive oxygen species (ROS) generated by poor therapy and function as protective agents. Autophagy inhibition of Gd2 O3 enables excellent photothermal therapeutic effects on orthotopic gliomas and protection against inflammation in normal cells. The results of this study may prove useful in developing highly efficient nanomedicines for glioma treatment.

ABRACL as a potential prognostic biomarker and correlates with immune infiltration in low-grade gliomas

BackgroundLow-gradegliomas (LGGs) as one of the mostcommonbrain tumors and highlyinvadeinto adjacent normal brain tissue, which can result in low rate of radical excision and poor prognosis. Immunotherapy as a potential treatment method has garnered increasing attention in recent years. Wesystematically screenedthe prognosticgenes based on 56,530 genes in CGGA database. Finally, ABRACL was selected as the target gene. ABRACL has not been investigated in gliomas. In our study, we aimed to explore the prognostic value of ABRACL. MethodsTo analyse the prognostic value of ABRACL, gene expression profiles and clinical information of LGGs patients were collated from theTCGAandCGGAdatabases. Functional enrichment analysis was performed by using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). CIBERSORTalgorithm was used to calculate the associations between ABRACL and immune cells infiltration. Then, we investigated the associations between ABRACL and immunomodulators. Four immunomodulators (TNFRSF14, TNFSF13, ULBP1, PDCD1LG2) were selected to establish theprognosticmodel which could be used to predict outcomes of LGGs patients. ConclusionLGGs patients with high expression of ABRACL showed worse prognosis. ABRACL was an independent prognostic factor of LGGs. ABRACL played an important role in tumor immune microenvironment and promoted tumorigenesis and proliferation of LGGs by regulating the aggregation of macrophages M2. Functional enrichment analysis suggested that ABRACL was associated with various immune functions. Taken together, the results of this study showed that ABRACL was apotentialnovel biomarker of LGGs.

DIPG-14. Neogenin Knockout Stops the Invasion and Dissemination of Diffuse Intrinsic Pontine Gliomasin vivo.

INTRODUCTION: Diffuse Intrinsic Pontine Glioma (DIPG) is a devastating high-grade glioma localized in the brainstem that occurs almost exclusively in children. The significant mortality rates of DIPG stem largely from its capacity to invade adjacent normal brain. We have previously published studies identifying the axon guidance factor, neogenin as a key driver regulating brain tumor cell invasion in medulloblastoma, glioblastoma and DIPG in vitro. Here we expand this work with an in vivo model to validate neogenin as promising inducer of DIPG invasion. METHODS: CRISPR-Cas9 system was used to knock-out the neogenin gene in DIPG cells. After validation of the knockout (KO) in vitro by RTqPCR, Western blot, and immunofluroresence, the cells were orthotopically implanted in the pons of nude mice (n=8/group) with a stereotactic frame. Tumor growth and dissemination were monitored using the In Vivo Imaging System (IVIS). Then, brains and spinal cords were collected, and H&E staining was performed. RESULTS:In vitro studies confirmed the KO of neogenin in DIPG cells. In vivo studies revealed that the neogenin total KO group had no progression of the tumor without any dissemination after 4-6 weeks, in marked contrast to the WT group, which exhibited steady growth and widespread dissemination into the spine. Immunohistochemistry confirmed the IVIS results. CONCLUSION: Expanding on previous work, this data suggests that neogenin is a major contributor of DIPG cell invasion and dissemination. The blockade of neogenin in DIPG cells demonstrates the potential utility of neogenin as potential therapeutic target, capable of reducing tumor growth and stopping tumor cell dissemination.

Pulsed Microwave-Induced Thermoacoustic Shockwave for Precise Glioblastoma Therapy with the Skin and Skull Intact.

Glioblastoma has a dismal prognosis and is a critical and urgent health issue that requires aggressive research and determined clinical efforts. Due to its diffuse and infiltrative growth in the brain parenchyma, complete neurosurgical resection is rarely possible. Here, pulsed microwave-induced thermoacoustic (MTA) therapy is proposed as a potential alternative modality to precisely and effectively eradicate in vivo orthotopic glioblastoma. A nanoparticle composed of polar amino acids and adenosine-based agonists is constructed with high microwave absorbance and selective penetration of the blood-brain barrier (BBB) at the tumor site. This nanoparticle can activate the adenosine receptor on the BBB to allow self-passage and tumor accumulation. The nanoparticle converts absorbed microwaves into ultrasonic shockwaves via the thermoacoustic cavitation effect. The ultrasonic shockwave can mechanically destroy tumor cells within a short range with minimal damage to adjacent normal brain tissue due to the rapid decay of the ultrasonic shockwave intensity. The deep tissue penetration characteristics of the microwave and the rapid decay of the ultrasonic shockwave make MTA therapy a promising glioblastoma cure including intact skin and skull.

MiR‑497/MIR497HG inhibits glioma cell proliferation by targeting CCNE1 and the miR‑588/TUSC1 axis.

Emerging evidence has shown that microRNA (miR)-497 serves pivotal roles in tumorigenesis, cancer progression, metastasis and chemotherapy resistance in several types of cancer. In the present study, the expression and biological functions of miR-497 host gene (MIR497HG) were investigated in glioma tissue. The expression levels of miR-497 and MIR497HG were measured in glioma, adjacent non-cancerous and normal brain tissue and their association with the prognosis of patients with glioma were analyzed. The biological roles of miR-497 and MIR497HG were investigated in glioma cell lines. In addition, bioinformatics analysis, luciferase reporter assay and functional experiments were performed to identify and validate the downstream targets of miR-497 or MIR497HG. The expression levels of miR-497 and MIR497HG were downregulated in glioma tissue and cell lines compared with those in adjacent non-cancerous and normal brain tissue and normal human cortical neuron cell line. Patients with low miR-497 or MIR497HG expression levels exhibited a poor prognostic outcome. In addition, forced overexpression of miR-497 or MIR497HG significantly inhibited the proliferation and cell cycle progression of glioma cell lines. Furthermore, the results indicated that miR-497 and MIR497HG exerted their biological functions by direct targeting of cyclin E1 and miR-588/tumor suppressor candidate 1. In summary, the data indicated that miR-497 and MIR497HG served as tumor suppressors and may be used as potential therapeutic targets and prognostic biomarkers in glioma.

Malignant Tumor Purity Reveals the Driven and Prognostic Role of CD3E in Low-Grade Glioma Microenvironment.

The tumor microenvironment (TME) contributes to the initiation and progression of many neoplasms. However, the impact of low-grade glioma (LGG) purity on carcinogenesis remains to be elucidated. We selected 509 LGG patients with available genomic and clinical information from the TCGA database. The percentage of tumor infiltrating immune cells and the tumor purity of LGG were evaluated using the ESTIMATE and CIBERSORT algorithms. Stromal-related genes were screened through Cox regression, and protein-protein interaction analyses and survival-related genes were selected in 487 LGG patients from GEO database. Hub genes involved in LGG purity were then identified and functionally annotated using bioinformatics analyses. Prognostic implications were validated in 100 patients from an Asian real-world cohort. Elevated tumor purity burden, immune scores, and stromal scores were significantly associated with poor outcomes and increased grade in LGG patients from the TCGA cohort. In addition, CD3E was selected with the most significant prognostic value (Hazard Ratio=1.552, P<0.001). Differentially expressed genes screened according to CD3E expression were mainly involved in stromal related activities. Additionally, significantly increased CD3E expression was found in 100 LGG samples from the validation cohort compared with adjacent normal brain tissues. High CD3E expression could serve as an independent prognostic indicator for survival of LGG patients and promotes malignant cellular biological behaviors of LGG. In conclusion, tumor purity has a considerable impact on the clinical, genomic, and biological status of LGG. CD3E, the gene for novel membrane immune biomarker deeply affecting tumor purity, may help to evaluate the prognosis and develop individual immunotherapy strategies for LGG patients. Evaluating the ratio of differential tumor purity and CD3E expression levels may provide novel insights into the complex structure of the LGG microenvironment and targeted drug development.

Long non‑coding RNA NEAT1 regulates glioma cell proliferation and apoptosis by competitively binding to microRNA‑324‑5p and upregulating KCTD20 expression.

Previous studies have demonstrated that long non-coding RNAs (lncRNAs) serve a key role in the development and progression of several types of cancer, including glioma. The lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) contributes to cancer growth through its effects on cell proliferation, migration, invasion and drug resistance. However, the exact regulatory mechanisms via which NEAT1 acts in glioma are unclear. In the present study, the expression levels and function of NEAT1 in glioma tissues and cell lines were examined in vitro and in vivo. By reverse transcription-quantitative PCR and fluorescence in situ hybridization analysis, NEAT1 expression was upregulated in glioma tissues compared with in adjacent normal brain tissues, and elevated NEAT1 levels were associated with poor prognosis. Cell Counting Kit-8, colony formation, ethynyldeoxyuridine, flow cytometry and western blotting assays were performed to detect the effects of NEAT1 on cell biological behavior. Knockdown of NEAT1 in glioma cell lines was associated with cell cycle arrest at the G0/G1 phase, decreased proliferation and elevated apoptosis in vitro, and resulted in reduced tumor growth and increased survival in a mouse xenograft model of glioma. Using bioinformatics analysis, RNA immunoprecipitation experiments and luciferase reporter assays, it was demonstrated that NEAT1 may competitively bind to microRNA (miR)-324-5p, thus blocking its interaction with target mRNAs. Potassium channel tetramerization protein domain containing 20 (KCTD20) was identified as a specific miR-324-5p target. Accordingly, the inhibition of NEAT1 resulted in the downregulation of KCTD20 through competitive binding with miR-324-5p, decreased cell proliferation and increased apoptosis. Concomitant NEAT1 knockdown and inhibition of miR-324-5p partially reversed the effects of NEAT1 knockdown on cell proliferation and apoptosis, and further regulated KCTD20 expression. Collectively, the present findings demonstrated that NEAT1 acted as a competing endogenous RNA for miR-324-5p, and identified the NEAT1/miR-324-5p/KCTD20 axis as a novel regulatory axis and a potential therapeutic target for human glioma.

Up-regulation of long non-coding RNA BLACAT1 predicts aggressive clinicopathologic characteristics and poor prognosis of glioma.

Bladder cancer-associated transcript 1 (BLACAT1) is one of the most common cancer-associated long non-coding RNAs (lncRNAs), which has been reported as a tumor promotor in several malignancies. Previously, BLACAT1 was found to be overexpressed in glioma tissues and cell lines. Functional assays determined that BLACAT1 promoted glioma cell proliferation, migration, invasion and epithelial-mesenchymal transition, suggesting that BLACAT1 might serve as an oncogene in glioma. In the present study, we aimed to investigate its clinical significance and prognostic value in glioma patients.A total of 137 paired glioma tissue samples and adjacent normal brain tissue samples were collected from 137 glioma patients who underwent surgery from May 2014 to February 2019. The Student t test was applied to determine the statistical significance of the observed differences between 2 groups. Survival curves were constructed and differences among groups were calculated using the Kaplan–Meier method.The relative expression of BLACAT1 in glioma samples was significantly higher than that of matched normal tissues (P < .001). The expression level of tissue BLACAT1 was statistically correlated with tumor size (P = .04), Karnofsky Performance Status (KPS) (P = .006), and WHO grade (P = .017). Kaplan–Meier analysis with the log-rank test revealed that BLACAT1 up-regulation was correlated with shorter overall survival time of patients with glioma (Log Rank test, P = .012). In multivariate Cox analysis, BLACAT1 expression was found to be an independent prognostic factor for overall survival in patients with glioma (HR = 2.739; 95% CI: 1.785–8.229; P = .035). Our study demonstrates that up-regulation of BLACAT1 is able to predict aggressive clinicopathologic characteristics and poor prognosis of glioma patients. These findings may have significant implications for potential treatment options and prognosis for patients with glioma.

Nidogen-1 expression is associated with overall survival and temozolomide sensitivity in low-grade glioma patients.

We investigated the prognostic significance of nidogen-1 (NID1) in glioma. Oncomine, GEPIA, UALCAN, CCGA database analyses showed that NID1 transcript levels were significantly upregulated in multiple cancer types, including gliomas. Quantitative RT-PCR analyses confirmed that NID1 expression was significantly upregulated in glioma tissues compared to paired adjacent normal brain tissue samples (n=9). NID1 silencing enhanced in vitro apoptosis and the temozolomide sensitivity of U251 and U87-MG glioma cells. Protein-protein interaction network analysis using the STRING and GeneMANIA databases showed that NID1 interacts with several extracellular matrix proteins. TIMER database analysis showed that NID1 expression in low-grade gliomas was associated with tumor infiltration of B cells, CD4+ and CD8+ T cells, macrophages, neutrophils, and dendritic cells. Kaplan-Meier survival curve analysis showed that low-grade gliomas patients with high NID1 expression were associated with shorter overall survival. However, NID1 expression was not associated with overall survival in glioblastoma multiforme patients. These findings demonstrate that NID1 expression in glioma tissues is associated with overall survival of low-grade glioma patients and temozolomide sensitivity. NID1 is thus a potential prognostic biomarker and therapeutic target in low-grade glioma patients.

Shear wave elastography for intracranial epidermoid tumors

BackgroundUltrasound elastography (USE) is a novel technique that assesses the mechanical properties of body tissues in real time. Based on elasticity measurements, USE enables the differentiation of tumor tissue from surrounding normal tissue. ObjectivesWe aimed to evaluate an intraoperative SWE technique for differentiating tumor tissue (epidermoid cyst) from the surrounding normal brain tissue based on elastic properties. MethodsWe prospectively report the intraoperative elasticity assessments of four patients diagnosed with epidermoid cysts. Along with standard ultrasonography, intraoperative shear wave elastography (SWE) was used to identify tumor tissue and assess the elasticity of each tumor and the surrounding normal brain. ResultsUSE enabled the differentiation between epidermoid cysts and the surrounding normal brain tissue in real time intraoperatively; visual data (SWE elasticity map) and quantitative data (elasticity measurements in kilopascals) were utilized to identify the epidermoid cyst based on its elastic properties. The area representing the epidermoid cyst had an increased elasticity on SWE view and high mean elasticity values (193.7 ± 70.9 kPa in case 1, 168 ± 24.5 kPa in case 2, 205.1 ± 6.7 kPa in case 3, and 101.3 ± 12.6 kPa in case 4). The area representing the adjacent normal brain tissue on SWE view had lower mean elasticity values (14.9 ± 1.9 kPa in case 1, 22.6 ± 8.3 kPa in case 2, and 23.8 ± 1.4 kPa in case 4). ConclusionThis study demonstrates the feasibility and promising value of SWE as an intraoperative tool during epidermoid cyst resection. Epidermoid tissue remnants that are hidden from the microscopic view can be detected using SWE.

Association Between Macrophages with Angiogenic Cells and Microvascular Dysfunction in Astrocytic Glioma

Objectives: Astrocytic gliomas are the most common primary brain tumours that developed from glial origin. Macrophages are the predominant inflammatory cells in infiltrating gliomas. The study aimed to investigate the association between circulating macrophages with tissue resident angiogenic cells and microvascular dysfunction in astrocytic glioma. Methods: A total of 22 astrocytic glioma patients were consented from Hospital Universiti Sains Malaysia. Tumour (n=22) were sliced and stained with CD133+ and VEGFA+ angiogenic markers and counter stained with DAPI. The Spearman rho’s test was used for the data analysis. The plasma CD68, macrophage level and von Willebrand factor level or factor VIII level (vWF/ FVIII) was measured using Elisa Kit (CUSABIO BIOTECH CO., LTD). Results: The mean plasma CD68 macrophages was 12.48±19.98 pg/ml. The mean percentage of brain tumour tissue angiogenic cells was (1.26±0.95%), adjacent normal brain tissue angiogenic cells was (0.72±0.68%). Spearman’s rho correlation test showed a significant correlation between brain tumour angiogenic cells and plasma CD68 macrophages (n=22) (Spearman’s rho, r=0.43, p=0.047). However no correlation was observed between plasma CD68 macrophages with adjacent normal brain (Spearman’s rho r =0. 019, p=0. 932). In this study vWF/FVIII level was analysed and about 14 patients with (mild factor level of >5%), 8 patients with (moderate factor level of 1-5%) and no patients had (severe factor level of <1%) was found. The mean vWF/FVIII percentage patient with mild level was 12.48±7.77 % and moderate vWF/FVIII factor level was 3.53±1.32%. The spearman’s rho correlation test showed a significant correlation between patient with moderate vWF/FVIII level with plasma CD68 macrophages (Spearman’s rho r=0.73, p=0.041). Conclusion: Circulating macrophages associated with brain tumour angiogenic cells and vWF/FVIII of astrocytic glioma. Thus targeting these parameters in the treatment of glioma might be useful. Keywords: Angiogenic cells, astrocytic glioma, brain tumour, macrophages, microvascular dysfunction

Possible Overcoming of Tumor Hypoxia with Adaptive Hypofractionated Radiosurgery of Large Brain Metastases: A Biological Modeling Study.

The present biological modeling study evaluated possible application of adaptive hypofractionated stereotactic radiosurgery (HSRS), which involves escalation of the prescription dose according to the gradual decrease in the tumor volume between treatment sessions separated by 2- to 3-week intervals, in the management of large brain metastases. To investigate the effects of dose escalation during three-stage adaptive HSRS, a generalized biologically effective dose (gBED) model was applied. Accounting for both a nonuniform dose distribution inside the target and tumor hypoxia was implemented, and normal brain radiation dose distributions were assessed. In comparison with conventional three-stage HSRS (with an identical prescription dose of 10 Gy at each treatment session), adaptive HSRS resulted in a 30-40% increase in gBED. This effect was especially prominent in late-responding targets (with α/βratios from 3 to 10Gy) and in neoplasms containing a high percentage of hypoxic cells. Despite dose escalation in the target, irradiation of the adjacent normal brain tissue was kept within safe limits at a level similar to that applied in conventional three-stage HSRS. Adaptive HSRS theoretically results in significant enhancement of gBED in the target and may possibly overcome resistance to irradiation, which is caused by tumor hypoxia. These advantages may translate into higher treatment efficacy in cases of large brain metastases.

Screening and functional prediction of differentially expressed circular RNAs in human glioma of different grades.

Circular RNAs (circRNAs) have a critical regulatory function in human glioma. However, novel circRNAs related to different pathological grades of glioma and their crucial potential function are worth screening and prediction. CircRNA expression profiling was performed for 6 paired high- and low-grade glioma tissues and 5 adjacent normal brain tissues through next-generation sequencing. Quantitative real-time PCR (qRT-PCR) was conducted to validate circRNA expression. Bioinformatics analysis was performed, and circRNA-miRNA-mRNA networks were constructed. The expression and survival data of miRNAs and target genes were examined by GEPIA, Chinese Glioma Genome Atlas (CGGA), ONCOMINE, and cBioPortal databases. The RNA binding proteins (RBPs), open reading frames (ORFs) and N6-methyladenosine (m6A) modifications of the identified circRNAs were also predicted. Through multilevel research screening, 4 circRNAs (hsa_circ_0000915, hsa_circ_0127664, hsa_circ_0008362, and hsa_circ_0001467) were associated with glioma of different pathological grades and could be preferred candidates for subsequent functional analysis. Therefore, circRNAs are associated with the different pathological grades of glioma and reveal their potential critical regulatory function. CircRNAs might provide vital molecular biomarkers and potential therapeutic targets for glioma.

Association of Angiogenic Cells in the Tumour Microenvironment and the Circulating Matured Endothelial Cells in Astrocytic Glioma

Introduction: Astrocytic gliomas are the most common and lethal intracranial brain tumours and rely on angiogenesis for the tumour development. Endothelial progenitor cells (EPCs) contribute to the angiogenesis of glioma tumour. Objectives: The study aimed to investigate the matured circulating endothelial cells population in the peripheral blood mononuclear cells (PBMCs) and its associations with tissue resident angiogenic cells in astrocytic glioma patients. Methods: A total of 22 astrocytic glioma patients were recruited from Hospital Universiti Sains Malaysia. Tumour were sliced and stained with CD133+ and VEGFA+ for angiogenic cells (n=22). The circulating (CD133-/VEGFR2+) matured endothelial cells in PBMCs (n=22) were quantified using FACS. The paired t-test and Pearson correlation test were used for the data analysis. Results: The angiogenic cells in brain tumour tissue were significantly higher compared to adjacent normal brain tissue (median 1.07±0.96% vs. median 0.69±0.68%; Wilcoxon signed rank test Z=-3.100; p=0.002). Positive correlation was found between the angiogenic cells of brain tumour tissue and adjacent normal brain tissue (Spearman’s rho correlation test, r=0.56; p=0.007). Significant positive correlation was found between matured endothelial cells in peripheral circulating systems and angiogenic cells in tumour of astrocytic glioma patients (Pearson correlation test, r=0.60, p=0.003).Conclusion:The findings of the study give support to the possible roles of EPCs in astrocytic glioma patients. Thus targeting tissue resident angiogenic cells and matured circulating endothelial cells by antiangiogenic treatment might be useful to prevent the tumour growth.